This invention relates to a method of and an apparatus for washing a substrate such as semiconductor wafer, glass substrate for liquid crystal, and substrate for photomask.
A brush scrub method has been generally used to remove particles such as dust attached to the surface of a substrate. According to this method, particles are removed by rubbing the surface of the substrate placed on a rotary substrate support by a nylon brush or the like while wash water is supplied to the surface of the substrate.
In the brush scrub method, however, there has been the problem that particles having been removed from the surface of a substrate, e.g., an oxide layer of a semiconductor wafer, are liable to reattach to the substrate due to electrostatics produced on the surface of the substrate by friction of the brush and the surface.
Also, particles attach to the brush due to the electrostatics produced by the friction. Accordingly, there is the problem that attached particles are liable to attach to a new substrate.
Further, dust is generated by bristles of the brush by rubbing the substrate by the brush. This causes the brush to be a source of dust.
Relatively large particles, having a diameter of about 0.3 .mu.m, can be removed by the brush scrub method. However, it is difficult to remove fine particles having a diameter of about 0.1 .mu.m because they pass between the bristles of the brush.
These problems have occurred in production of a variety of substrates such as semiconductor wafers, glass substrates for liquid crystals, and substrates for photomasks.